Aquatronica Level Interface as AC on/off inticator

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Hi Guys and Gals

I recently bought a Aquatronica controller from @Nippy. I must say that it has change my life for the better. I can go away for a weekend without the constant worry about the tank.

I know that Aquatronica has been neglected from a support perspective but it remains a solid aquarium controller.

The one problem I was faced with was if the power goes off the controller was not aware of the power failure until the UPS dies. So what I did was run the main plug bar off the UPS and the second plug bar off the Main power. So basically the essentials on UPS and non-essentials on main power. At first this worked really well but I soon ran out of plug space on the non-essential bar and had open plugs on the essential bar.

So I googled it and came up empty handed. I spoke to Matthew from Nemo's Janitor about it and he suggested I use one of the level sensor interfaces.

So I started fiddling with a spare float switch I had. Connecting it directly to the interface. It did pick up a level sensor but had weird readings and disconnect status. SO again back to google for help with no luck again! Was I the first person to try this or did nobody share this before.

The controller had its own level switch and I took my multi meter and took an ohm reading when the switch was on and off. Sure enough it was not a simple 0 and 1 reading. 470 ohms when open and 300 ohms when closed.

I took and old PSU that was struck by lightning and started measuring resistors. Could not find exactly the resistance I was looking for but resistors in series also works :)

Just hooked it up to the float switch and Voila! It was working. The controller picked it up as a new level sensor and it worked perfectly.

So now to get the controller to know when the power is on or off.

I bought a 12v relay for a DIY ATU I used before I had the controller. This would serve as my on/off switch very nicely :) I connected the relay power source to the main power. While the power is on the relay is connected. If the power goes off the relay is released changing the sensor to off. PLEASE NOTE: I am using the relay as a switch only. There is no power going back to the Aqutronica controller.

This is what the relay looks like when it was a prototype.

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I have since refined the design by using 2 resistors in parallel to get the correct results. (470 ohm when open and added 830 when closed to result in 300 ohm reading)

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So now my plug bars are both connected to the UPS and configured to switch off all non essentials if the power has gone off for more that 5 seconds.

I will be glad to assist anyone that needs more help or information. Please feel free to PM me.

On a side note. For the sensor connector on the interface I used the PSU main connect to the motherboard. I just sawed two prongs off. This is exactly what you need one square and one D-type connector.

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Warning: Please don't fry your controller by doing something stupid. Only do this if you know what you are doing. I take no responsibility if you frying your controller. :)
 
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Nice work.
Sorry if this sounds like a stupid question, but what is going through the float switch, 12v or 220v?

This is not a stupid question. The controller does pass through a small current (5V DC) to get the ohm readings. So using a 220V float switch might not work. I will never own a 220V float switch so I cannot test it. Hope this clears it up.
 
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